There are subtle signs of a new eruption brewing on Russia’s Kamchatka Peninsula. The Earth-Observing 1 satellite captured ash above Zhupanovsky Volcano on November 5, 2013 (top image). According to the Global Volcanism Program, the explosions at Zhupanovksy are phreatic, caused by the nearly instantaneous vaporization of water with hot material below the surface.

In this natural-color image, snow on the high-altitdue ridges is white, ash is light gray, bare rock is tan, and the deeply shadowed northern slopes of Zhupanovsky Massif are blue.